Final Presentation

Description

Presentations of the projects are given a few days after the Final Demo to an audience of fellow student reviewers, the lab instructors, and occasionally faculty or even students from outside the class who are following up a project of personal interest to them. The style is formal and professional, and students should dress accordingly (Generally business professional, or what you would wear to a career fair).

Requirements and Grading

Each project team has 25 minutes for a Powerpoint presentation and questions. Every group member must present their own work contributing to the project and be ready to answer questions. Presentations are judged on the basis of presentation technique and of technical organization and content.

Presentation technique includes dress, use of display materials (slides), clarity of speech, absence of filler words/fidgeting, proper eye contact with audience and smooth transitions between speakers. Content is judged on use of a proper introduction, orderly and connected development of ideas, absence of unnecessary details, proper pacing to stay within the allotted time, and an adequate summary at the close of the talk. Quantitative results are expected whenever applicable. Here is a general outline to follow:

  1. Introduction to your team and your project.
  2. Objective. What problem are you solving?
  3. Brief review of original design, statement on areas of design that changed, and overview of each functional block's requirements.
  4. Description of project build and functional test results. You can choose to include a short (30s) video of your project here.
  5. Discussion of successes and challenges, as well as explanations of any failed verifications demonstrating and understanding of the engineering reason behind the failure
  6. Conclusions from the project: what did you learn, what would you do differently if you redesigned your project, etc.
  7. Recommendations for further work.

Any significant, relevant ethical issues should be briefly addressed, preferably in a single slide.

Presentations will be graded using the presentation grading rubric. Your slides should follow ECE or College of Engineering presentation theming.

Submission and Deadlines

Slides for your final presentation must be uploaded to your project page on PACE prior to your presentation time. Deadlines for signing up may be found on the Calendar. Sign-up for the final presentation is done through PACE. Remember to sign up for a peer review of another group.

Active Cell Balancing for Solar Vehicle Battery Pack

Tara D'Souza, John Han, Rohan Kamatar

Featured Project

# Problem

Illini Solar Car (ISC) utilizes lithium ion battery packs with 28 series modules of 15 parallel cells each. In order to ensure safe operation, each battery cell must remain in its safe voltage operating range (2.5 - 4.2 V). Currently, all modules charge and discharge simultaneously. If any single module reaches 4.2V while charging, or 2.5V while discharging, the car must stop charging or discharging, respectively. During normal use, it is natural for the modules to become unbalanced. As the pack grows more unbalanced, the capacity of the entire battery pack decreases as it can only charge and discharge to the range of the lowest capacity module. An actively balanced battery box would ensure that we utilize all possible charge during the race, up to 5% more charge based on previous calculations.

# Solution Overview

We will implement active balancing which will redistribute charge in order to fully utilize the capacity of every module. This system will be verified within a test battery box so that it can be incorporated into future solar vehicles.

Solution Components:

- Test Battery Box (Hardware): The test battery box provides an interface to test new battery management circuitry and active balancing.

- Battery Sensors (Hardware): The current battery sensors for ISC do not include hardware necessary for active balancing. The revised PCB will include the active balancing components proposed below while also including voltage and temperature sensing for each cell.

- Active Balancing Circuit (Hardware): The active balancing circuit includes a switching regulator IC, transformers, and the cell voltage monitors.

- BMS Test firmware (Software): The Battery Management System requires new firmware to control and test active balancing.

# Criterion for Success

- Charge can be redistributed from one module to another during discharge and charge, to be demonstrated by collected data of cell voltages over time.

- BMS can control balancing.

- The battery pack should always be kept within safe operating conditions.

- Test battery box provides a safe and usable platform for future tests.